The present invention relates to a manufacturing method of a semiconductor device, an exposure method, and an exposure apparatus, and specifically relates to a manufacturing technique of a semiconductor device including an exposure step using EUV light.
In a manufacturing process of a semiconductor device, the lithography (exposure and development) technique is used as a technique of forming a pattern on a principal surface of a semiconductor substrate (wafer). A projection exposure apparatus is mainly used for this lithography, and a mask pattern formed on the photo-mask is transferred onto the resist by irradiating resist coated on the principal surface of the wafer with exposure light transmitted through a mask (original copy) mounted on this projection exposure apparatus.
Recently, a higher integration of a semiconductor element and a higher operation speed of the semiconductor element have been required and pattern miniaturization has been developed to satisfy these requirements. Further, to satisfy this requirement of miniaturization, effort to improve resolution of a projected image has been promoted by using a shorter wavelength for an exposure light wavelength. For example, a lithography technique which uses EUV (Extreme Ultra-Violet) light having a wavelength of 13.5 nm one digit or more shorter than the ultra-violet laser region of KrF (248 nm) and ArF (193 nm) in the related art has been studied.
For example, Japanese Patent Laid-Open No. 2007-109451 (Patent Document 1) discloses an initial alignment method of an extreme ultra-violet light source apparatus as follows. First, a first positional reference element is disposed at an ideal emission point and a second positional reference element is disposed at an ideal focus. Next, a light path of first optical axis adjustment light is adjusted so that first optical axis adjustment light passes through the first positional reference element and the second positional element, and also a light path of second optical axis adjustment light is adjusted so that the second optical axis adjustment light passes through the first positional reference element and does not pass through the second positional reference element. Further, the light path of laser light is adjusted so that the laser light irradiates the first positional reference element and also a target material is aligned so that the target material passes through a cross point of the first optical axis adjustment light and the second optical axis adjustment light. After that, the position and posture of a condenser mirror is adjusted so that extreme ultra-violet light generated from plasma is condensed at the second positional reference element by the condenser mirror.